This invention concerns 2-cycle engines that are fitted to brush cutters, backpack power sprayers, etc., and in particular concerns 2-cycle engines which realize a reduction in total hydrocarbons (THC).
With 2-cycle engines fitted to brush cutters or backpack power sprayers, etc., an air-fuel mixture in the crankcase is introduced into the combustion chamber through transfer ports when there is scavenging, and while the combustion chamber is scavenged the combustion chamber is filled.
With conventional 2-cycle engines, air-fuel mixture introduced into the combustion chamber through transfer ports is not left in the combustion chamber, but rather, the mixture is purged out through the outlet port and released into the atmosphere as un-burnt gas, making it a cause of air pollution.
The purpose of this invention is to provide the 2-cycle engine that can effectively reduce the amount of air-fuel mixture purged out through the outlet port.